Weathering rates of buried machine‐polished rock disks, Kärkevagge, Swedish Lapland

Abstract

AbstractSome 48 dolomite, 37 granite, and 19 limestone machine‐polished disks were buried at soil horizon boundaries in 16 soil pits to maximum depths of 0·5–0·6 m within Kärkevagge, a presently periglacial, glaciated trough in Arctic Sweden. The objective of the ongoing study is to determine near‐surface ‘potential’ weathering rates beneath birch forest, Dryas heath, heath, meadow, solifluction meadow, and willow vegetation cover types. Selected disks were excavated after 1 year, and all disks were excavated after 4 or 5 years.The limestone disks weathered fastest, followed closely by the dolomite disks, but the granite disks weathered at much slower rates. Mean annual percentage mass loss over 4 or 5 years was 0·473 ± 0·145% (two standard errors) for dolomite disks, 0·032 ± 0·005% (two standard errors) for granite disks, and 1·104 ± 0·446% (two standard errors) for limestone disks. For dolomite disks the Dryas heath and heath environments weathered the most slowly, a trend that was generally followed by the granite disks. Poor drainage (i.e. increasing wetness) and decreasing pH were found to promote dolomite weathering rates in a statistically significant manner. Surficial and subsurface weathering rates at individual sites were generally found to be correlated for dolomite, but not granite. Copyright © 2002 John Wiley & Sons, Ltd.